1. Field of the Invention
The present invention relates to a weather strip for a door belt-molding and, in particular, to a weather strip which is intended to be retained in contact with a slidably movable window glass.
2. Description of the Related Art
FIG. 4 of the accompanying drawings illustrates the cross-sectional configuration of a well known conventional vehicular door belt-molding designed for placement along at least the bottom edge of a window opening to serve both as a finishing cover for the door edge at the periphery of the opening, and as a weather strip or seal between the door structure and a window glass movable in the plane of the door to and from a position closing the opening. A weather strip 1 is shown in an initial or relaxed condition relative to the closed position of a window glass 2, and carries on the side thereof facing the window glass 2, a flocked portion 3. The weather strip 1 extends from a root portion a through which it is connected as an integral portion of a door belt-molding 4 extending about a stainless steel core 5.
In this type of weather strip, movement of the window glass 2 to and from its closed position results in sliding contact with the flocked portion 3, and flexure of the weather strip 1 at the root portion a in a manner to retain the flocked portion under a yieldable bias against the window glass. The weather strip 1 thus functions to remove foreign matter such as water droplets, dust, etc. from the window glass 2 during up and down sliding movement of the window glass 2.
The weather strip 1, including the root portion a thereof, is made of a vinyl chloride having adequate elasticity to permit flexure from the position illustrated to a position in which the flocked portion lies against the facing surface of the window glass 2. The vinyl chloride material of the weather strip 1 has good properties for ensuring continuous fluid-tight contact with the glass but tends to develop a permanent strain when flexed under a continuously applied force. As a result, the pressure exerted by the window glass 2 acts on the root portion a to develop a permanent strain so that, with passage of time, the biasing force, which retains the weather strip 1 against the window glass 2, is decreased. Accordingly, function of the flocked portion 3 for removing water and other foreign matter from the window glass 2 is diminished, if not eliminated. Thus, the conventional weather strip 1 leads to such drawbacks as streaking and other impairments to vision through the window glass.